Endocardial lead extraction apparatus and method

ABSTRACT

A composite assembly includes a first catheter having a lead grasping mechanism extending through a channel thereof, a second catheter concentrically disposed over the first catheter and having a smooth, tapered end and a third catheter concentrically disposed over the second catheter and is used to remove an inoperative endocardial lead from a patient&#39;s heart through a venous path. A free end of the lead is grasped and held securely to the first catheter by a grasping mechanism. The second and third catheters then are slid as a unit through the venous path over the grasped end of the lead as opposing tensile force is maintained on the first catheter to prevent movement of the lead. The second catheter is rotated to cause its smooth, tapered, leading edge with outward sharp serrations to separate scar tissue from the lead and dilate a path through the scar tissue. The third catheter, which also has a smooth leading edge and outward sharp serrations is further advanced a predetermined amount forward over the second catheter and is rotated to separate and/or dislodge a tip of the lead which is embedded in scar tissue of the heart. The composite assembly along with the lead therein then is removed as a unit from the heart via the venous path without causing excessive forces to be applied to the vein or the wall of the heart.

This is a continuation, of application, Ser. No. 480,412, filed 3/30/83now U.S. Pat. No. 4,471,777.

BACKGROUND OF THE INVENTION

The invention relates to methods and apparatus for removal oftransvenous endocardial leads from a patient's heart and the venous paththereto.

In the past, various types of endocardial leads and electrodes thereofhave been introduced into different chambers of a patient's heartincluding the right ventrical, right atrial appendage, and atrium aswell as the coronary sinus. These flexible leads usually are composed ofan insulator sleeve that contains an implanted helical coil conductorthat is attached to an electrode tip. This electrode is placed incontact with myocardial tissue by passage through a venous access, oftenthe subclaven vein or one of its tributories, which leads to theendocardial surface of the heart chambers. The tip with the electrodecontact is held in place by trabeculations of myocardial tissue. Thetips of many available leads include flexible tines, wedges, orfinger-like projections which extend radially outward and usually aremolded from and/are integral with the insulating sheath of the lead.These tines or protrusions allow surrounding growth of tissue and scarin chronically implanted leads to fix the electrode tip in position inthe heart and prevent dislodgement of the tip during the life of thelead. In "acute placement+ of the electrode or tip a blood clot formsabout the flanges or tines (due to enzymes released as a result ofirritation of the trabeculations of myocardial tissue by the presence ofthe electrode tip) until scar tissue eventually forms, usually in threeto six months. The tines or wedges or finger-like projections allowbetter containment by the myocardial trabeculations of muscle tissue andprevent early dislodgement of the lead tip. Other types of "screw-in"tips include the electrodes described in U.S. Pat. Nos. 4,209,019 and3,974,834, assigned to Medtronic, Inc. Although the state of the art inimplemented pulse generator or pacemaker technology and endocardial leadtechnology has advanced considerably, endocardial leads neverthelessoccasionally fail, due to a variety of reasons, including breakage of alead, insulation breaks, breakage of the inner helical coil conductorthereof and increase in electrode resistance. Also, in some instances,it may be desirable to electronically stimulate different portions ofthe heart than are presently being stimulated with leads already inplace. There are a considerable number of patients who have one or more,and sometimes as many as four or five unused leads in their veins andheart.

Although it obviously would be desirable to be able to easily removesuch unused leads, in the past surgeons usually have avoided attempts toremove inoperative leads because the risk of removing them exceeded therisk of leaving them in. The risks of leaving unused myocardial leads inthe heart and venous path include increased likelihood that an old leadmay be the site of infection which may necessitate removal of the leadto prevent continued bacteremia and abcess formation which, in turn, maylead to fatal complications. Furthermore, there is an increasedlikelihood of the formation of blood clots in the atrial chamber aboutentangled leads. Such clots may embolize to the lung and produce severecomplications and even fatality. Furthermore, the presence of unusedleads in the venous pathway and inside the heart can cause considerabledifficulty in the positioning and attachment of new endocardial leads inthe heart.

Thus, it is clear that the potential for infection and othercomplications increases rapidly as a number of old or unused endocardialleads in the heart and venous pathway increases.

Removal of an inoperative lead sometimes can be accomplished by applyingtraction and rotation to the outer free end of the lead but only if doneprior to fixation of the lead tip in the trabeculations of myocardialtissue by scar formation or large clot development. Even then, it ispossible that a clot has formed so the removal of the leads causesvarious sized emboli to pass to the lungs, producing severecomplications.

In cases where the lead tip has become attached by scar tissue to themyocardial wall, removal of the lead always has presented major problemsand risks. Porous lead tips that are sometimes used may have ingrowth ofscar tissue attaching them to the myocardial wall. Sufficient tractionon such leads in a removal attempt could cause disruption of themyocardial wall prior to release of the embedded lead tip, causingfatality. The tines or flanges of other types of leads that are nottightly scarred to the myocardial wall present similar risks. Even ifscrew-in tip electrodes of the kind mentioned in the Medtronic patentsreferred to above are used, wherein the tips theoretically can beunscrewed from the myocardial wall, unscrewing of such tips may beprevented by a channel of scar tissue and endothelium that surrounds theouter surface of the lead along the venous pathway. Such "channel scar"tissue prevents withdrawal because of tight encasement of the lead.Continual strong pulling or twisting of the outer free end of the leadcould cause rupturing of the right atrial wall or right ventricular wallif there is such tight circumferential encasement of adherent channelscar tissue in the venous path. Such tight encasement by scar tissue inthe venous pathway and in the trabeculations of the myocardial walltypically occurs within six months to a year of the initial placement ofthe lead.

The risks of removal of a lead by such traction and rotation of the leadare so high that if it becomes imperative that the lead be removed (asin the case of infection) most surgeons have elected to open thepatient's chest and surgically remove the lead rather than attemptremoval by applying traction and rotation thereto.

Clearly, there is a need for an improved method and apparatus forextracting "chronically placed" endocardial leads with minimal risk tothe patient.

Accordingly, it is an object of the invention to provide an improvedmethod and apparatus for extraction of endocardial leads with minimalrisk to the patient.

It is another object of the invention to allow placement of newendocardial leads and electrodes without interference by old leads inthe venous path or heart with the new leads.

It is another object of the invention to provide a method and apparatusfor removal of infected leads without the need for open chest surgery.

SUMMARY OF THE INVENTION

Briefly described, and in accordance with one embodiment thereof, theinvention provides a method and apparatus for removing an inoperativeendocardial lead from a patient's heart through a venous pathway bycontrolling a "lead grasping" mechanism which may extend through a firstcatheter to securely attach a free end of the lead to the leading end ofthe first catheter and, while maintaining tension on the lead graspingmechanism, sliding a second catheter disposed concentrically about thesurface of the first catheter over the attached end of the lead andalong the insulating surface of the lead to separate any adherent scartissue from the surface of the lead and, if necessary, dilating thevenous path as the second catheter is advanced toward the tip of thelead, which tip is tightly embedded in the wall of the heart by scartissue. In the described embodiments of the invention, the leading edgeof the second catheter is tapered, is very smooth, and is outwardlyserrated to enhance separation of the adherent scar tissue in the venouschannel from the surface of the lead and also to enhance dilation of thevenous path if necessary.

The tip portion of the second catheter is radiopaque to allowfluorescent visualization of the position of the radiopaque tip as thesecond catheter is advanced to the embedded tip of the lead. A thirdcatheter is concentrically disposed about the second catheter andinitially has a radiopaque, smooth outwardly serrated leading edgepositioned adjacent to the beginning of the tapered end portion of thesecond catheter. Both the second catheter and the third catheter arecomposed of semi-rigid but somewhat flexible plastic material. Both areadvanced as a unit as tension is maintained on the first catheter andthe lead attached thereto so they remain relatively stationary. As theleading end of the second catheter is advanced through the venouspathway, the second and third catheters are rotated together, causingthe outward serrations of the second catheter tip to enhance theseparation of adherent scar tissue from the lead. The smooth outwardlyserrated edge of the third catheter further clears the pathway throughthe venous channel, if necessary. After the leading portion of thesecond catheter has reached a shoulder of the embedded lead tip, thethird catheter is slid forward over the second catheter and is rotatedrelative to the second catheter so that its outward serrations separatescar tissue surrounding the embedded lead tip and/or forces the scartissue to break loose from the lead tip. At this point, the endocardiallead has its forward portion entirely inside the second catheter. Theendocardial lead, the second catheter, and the third catheter areremoved as a unit from the heart through the venous pathway and out ofthe patient.

In the described embodiments of the invention, the first, second andthird catheters are preassembled. Several embodiments of the graspingmechanism are described, including a first embodiment with three or moreoutwardly sprung grasping fingers each with an inwardly oriented clawand each attached to a stylet that extends through the channel of thefirst catheter and through a locking head disposed at the outer a distalend of the first catheter. The first catheter has a reinforced, slightlyenlarged chamber at its leading end. The open grasping fingers or clawsare positioned around the free end of the endocardial lead. Whiletraction is applied on the stylet wires at the opposite end of the firstcatheter to maintain the position of the lead, the first catheter isslid forward, its reinforced end portion forcing the claws or fingerstogether, causing them to close on and grasp the free end of the leadand hold it within the enlarged chamber. The locking head has slots forreceiving the end portions of the stylet wires and holding them inplace, thereby maintaining tension thereon and holding the lead securelyin the enclosed chamber. In another embodiment of the graspingmechanism, a circular or oval loop has attached thereto two or morestylet wires that extend through the center of the first catheter andare manipulated at the opposite or outer end of the first catheter totilt the loop after it has been positioned around the free end of thelead, thereby engaging the free end thereof. The leading end of thefirst catheter is slid so that its enlarged chamber slides over thetilted loop and the free end of the grasped lead. The stylet wires arebent into the slots of the locking head, thereby maintaining tension onthe grasping mechanism. In a third embodiment of the grasping mechanism,a screw-type end is provided on the end of cable element extendingthrough the first catheter and is rotated to screw it into the helicalcoil portion of the free lead end.

In a fourth embodiment of the grasping mechanism, a device known in theart as a "basket" is used. The basket grasper includes a number ofarc-shaped spring elements all connected at the rear end thereof to aneyelet or small loop through which a control stylet passes. The frontend of the control stylet is attached to the forward ends of all of thearc-shaped spring elements. Normally, with no tension on the stylet, thebasket is held in an elongated shape by the natural spring bias of thearch-shaped spring elements. When sufficient tension is maintained onthe controlled styled pulling it rearward and the position of the styletor loop is maintained, these forces cause the arc-shaped spring elementsto bow outward, increasing the widths of the gaps between the variousmutually adjacent arc-shaped spring elements. The position of the eyeletor loop is maintained by means of a flexible, semi-rigid tube orcatheter through which the control stylet extends. The tube and thecontrol stylet can extend through the center of the first catheter. Thecollapsible basket can be positioned so that the free end of theendocardial lead or some other portion thereof extends into one of theabove-mentioned gaps. The tension on the controlled stylet then isreleased, causing two-adjacent arc-shaped spring elements to closetightly upon the portion of the lead extending into the gap betweenthose two arc-shaped spring elements. The basket and the portion of thelead grasped thereby then are pulled into the enlarged chamber at theproximal end of the first or lead grasping catheter.

The described second and third catheters have reinforced leading tipportions into which plastic or metal inserts having smooth leading edgeswith sharp outward serrations are inserted. At the trailing end of thesecond catheter, an elongated torquing handle concentrically disposedabout the first catheter is attached to allow rotation of the secondcatheter relative to the first catheter, thereby allowing rotation ofthe serrated tip of the second catheter as it is advanced through thescar tissue in the venous channel. This enchances separating of the scartissue by the serrated edge. An enlarged second torquing handle isattached to the trailing end of the third catheter and disposedconcentrically about the first torquing handle. Initially, the secondtorquing handle is locked to the first torquing handle so that thesecond and third catheters rotate together. The locking means isdisengaged after the leading end of the second catheter has beenadvanced to its final position, allowing the second torquing handle tobe rotated relative to the first, thereby rotating the serrated tip ofthe third catheter and allowing it to separate scar tissue from theembedded tip as the third catheter is advanced a measured amount. Thedistance through which the third catheter is advanced over the secondcatheter is gauged by means of a scale on the first torquing handle asthe second torquing handle is slid along it.

In one described embodiment of the invention, the lead to be removed hasbroken inside the heart or the venous path, so its free outer end is notaccessible near the pulse generator. In this instance, a COOK introduceris used to position an open channel shaft through an opening into thevein and through the vein to a location adjacent to the free end of thebroken lead. The multi-catheter lead extracting assembly of theinvention is guided, by means of fluoroscopic visualizing of aradiopaque tip of the first (lead-grasping) catheter, through the openchannel of the shaft so that the open grasping mechanism surrounds thefree end of the lead. The stylet wires through the first catheter aremanipulated to close the grasping mechanism and attach it securely tothe leading end of the first catheter. The method of extracting the leadfrom this point on is as previously described.

If a composite dual lead of the type described in my U.S. Pat. No.4,332,259 is in place in a patient and must be exracted, the method andapparatus of the present invention can be used as explained previously,but first one of the leads, for example, the core lead, must be severedfrom the other. In order to accomplish this, a COOK introducer is usedas described above to position an open channel shaft or tube through anopening into the vein so that the proximal end of the open shaft or tubeis adjacent to the point at which it is desired to sever the cord leadextending out of the channel lead, typically into the ventrical of thepatient's heart. A semi-rigid catheter with a stop bar in its proximalend and a J-shaped or sickle-shaped inner knife edge attached to theproximal end of a control stylet extending through the catheter areinserted through the open channel shaft. The sickel-shaped knife elementis extended beyond the proximal end of the subject catheter and isguided under fluoroscopic visualization to loop around the core lead andpull it against the stop bar in the end of the catheter. Sufficienttension is applied to the control stylet to cause the knife edge to cutthrough the core lead. The upper portion of the core lead is withdrawninto the channel lead. The catheter and knife therein are withdrawn fromthe vein. The separated channel lead and core lead portions of thecomposite dual lead assembly then can be removed one at a time using thepreviously described extracting apparatus and method.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial elevation view of the first or lead graspingcatheter of the present invention.

FIG. 2 is a partial elevation view illustrating the grasping mechanismof the device shown in FIG. 1.

FIG. 3 is a partial cutaway view illustrating the . leading end of thelead grasping catheter of FIG. 1 grasping an endocardial lead.

FIG. 4 is a partial perspective view of a locking head which is attachedto the trailing end of the lead grasping catheter of FIG. 1.

FIG. 5 is a partial section view useful in illustrating and explainingthe locking head shown in FIG. 4 and is a section view along sectionline 5--5 of FIG. 4.

FIGS. 6A and 6B are partial diagrammatic perspective views useful inillustrating another embodiment of a lead grasping mechanism used inconjunction with a lead grasping catheter similar to the one shown inFIG. 1.

FIGS. 7A and 7B are partial perspective diagrammatic views useful inillustrating the use of the lead grasping mechanism shown in FIGS. 6Aand 6B.

FIGS. 8A, 8B and 8C are partial cutaway elevation views useful inillustrating a third lead grasping mechanism that can be used inconjunction with the lead grasping catheter of FIG. 1.

FIG. 9 is a partial elevation view showing the dilating catheter andouter ensheating catheter of the endocardial lead extraction apparatusof the present invention.

FIG. 10 is a partial perspective view illustrating the serrated leadingedges of either the dialating catheter or the outer ensheating catheterof the present invention.

FIG. 11 is a diagram of a heart in which an endocardial lead to beremoved is illustrated, the lead extraction apparatus of the presentinvention being shown in a partly advanced location along the lead.

FIG. 12 is an enlarged view of detail 12 of FIG. 11.

FIG. 13 is a partial cutaway perspective view useful in explaining useof the endocardial lead extraction system of the present invention.

FIG. 13A is a partial section view useful in describing the endocardiallead extraction system of the present invention.

FIGS. 14A-14F include a sequence of a partial cutaway elevation viewsuseful in describing utilization of the endocardial lead extractionapparatus of the present invention to extract an endocardial leadembedded in a patient's heart.

FIGS. 15A-15C are partial perspective views of an alternate leadgrasping mechanism.

FIGS. 16A and 16B are diagrams useful in explaining how to pre-cut acomposite dual lead assembly prior to using the lead extractingapparatus of the invention.

DESCRIPTION OF THE INVENTION

Referring now to the drawings, the endocardial lead extraction assemblyof the present invention will now be described. Although the device isassembled prior to use and has the configuration indicated in FIGS. 9,11, 13, 13A and FIGS. 14A-F, it will be helpful to understanding of theinvention to individually describe and illustrate three catheters ofwhich the assembly is composed. The inner catheter will be referred toby reference numeral 1 and is referred to herein as the "lead graspingcatheter". Several embodiments of the lead grasping mechanism thereofare described in FIGS. 1 through 8C. The second catheter that isconcentrically disposed about the lead grasping catheter 1 is referredto hereinafter as the "dilating catheter" and is designated by referencenumeral 3. The third catheter, which is concentrically disposed aboutthe dilating catheter 3, is referred to hereinafter as the "ensheathingcather" and is designated by reference numeral 5.

Referring now to FIG. 1, one embodiment of lead grasping catheter 1includes a flexible tube or sheath 1A having a leading end 7 and atrailing end 8. The leading end 7 is the end which is first insertedinto the venous pathway through which the inoperative lead is to beremoved. Protruding from leading end 7 of grasping catheter 1 are threeor more grasping claws designed by reference numeral 9. Grasping claws 9are sprung outward, as shown, and each is connected to a separatestylet, generally designated by reference numeral 9A. The stylets 9Aextend through the entire length of the channel of grasping catheter 1and extend an appreciable distance beyond the trailing or proximal end 8of grasping catheter 1.

Referring now to FIG. 2, reference numeral 11 designates an end portionof an inoperative lead 11 which is to be removed. Usually the free endof lead 11 is obtained when the lead is cut loose from an implantedpulse generator in the patient, or else it is a free end of a portion ofthe lead that is broken either in the venous pathway to the heart or inthe heart chamber itself. In any case, the open claws 9 are positionedaround the free end of lead 11. Referring now to FIG. 3, it should benoted that leading end 7 of lead 1 is reinforced, for example, by meansof a collar 13. The channel through lead grasping catheter 1 has areinforced, enlarged opening or chamber 14 in its lead end. The chamber14 is large enough that when a tension or traction force is applied onstylets 9A at the distal end of grasping catheter 1 in a directionindicated by arrow 15, and then the grasping catheter 1 is advancedalong the stylets 9A, which are being held stationary, toward lead 11 inthe direction indicated by arrow 16, the lead end 7 and the outer lip ofchamber 14 will slide along the outwardly sprung claws 9, forcing themto close upon and grasp the extreme end portion of lead 11, asillustrated in FIG. 3. In accordance with the invention, the tensileforce on stylus 9A holds them stationary as the grasping catheter 1moves forward until the grasped free end of lead 11 is securelypositioned in and held inside chamber 14. The, for all practicalpurposes of the invention, the free end of lead 11 is unitary withgrasping catheter 1.

Although not shown in FIG. 1, trailing end edge 8 of grasping catheter 1has preassembled thereon a locking head 18, shown in FIG. 5 in a partialsectional view and also shown in FIG. 4. Locking head 18 has as manyslots 19 therein as there are stylet wires 9A and claws 9, typicallythree or four. After the lead 11 has been grasped and drawn intoenlarged chamber 14 (FIG. 3), the three shown stylet wires 9A are bentoutwardly and around into the three slots 19, in the directionsindicated by arrows 20 in FIG. 5. This retains claws 9 and the graspedend of lead 11 securely in chamber 14, maintaining grasping catheter 1and lead 11 as a unitary member or "cord" during the remainder of thelead extraction operation.

FIGS. 6A, 6B, 7A and 7B disclose an alternate lead grasping apparatus toclaws 9. Referring now to FIG. 6A, a round stainless steel loop 22 isshown having three equally spaced peripheral points attached to threestylets 9A-1, 9A-2, and 9A-3. Initially, the plane of loop 22 isapproximately perpendicular to the axis 23 of the stainless steelstylets 9A, extending through the channel of lead grasper tube 1A. Asindicated in FIG. 6B, by applying opposed forces 24 and 25 to differentones of the stylets, the plane of loop 22 can be tilted in thedirections indicated by arrows 27. Referring now to FIG. 7A, it can beseen that when loop 22 is perpendicular to the axis of the lead grasperchannel, the loop 22 is positioned around the free end of myocardiallead 11. (Note that for convenience of illustration in FIGS. 6A, 6B, 7Aand 7B the grasping catheter tube 1A is omitted).

As shown in FIGS. 7A, loop 22 is positioned around the free end ofendocardial lead 11, and then opposed forces 24 and 25 are applied tothe sylet wires as shown in FIG. 7B in order to tilt the loop 22. Thetilted loop 22 thereby grasps the free end of lead 11. The leading end 7is moved forward in the direction indicated by arrow 16 in FIG. 3 asdescribed above, until loop 22 and the free end of lead 11 are tightlyencompassed in chamber 14, accomplishing, in essence, the same result asclaws 9.

As previously mentioned, endocardial leads ordinarily have a helicalcoil therein. Reference numeral 31 in FIGS. 8A-8C designates such ahelical coil. In accordance with another embodiment of the invention, asingle stylet 9A has a screw-tip 33 on the end thereof. As before, thegrasping catheter tube 1A is omitted for simplicity of illustration.Referring to FIG. 8B, the screw-tip 33 is screwed into the helical coil31 as the grasping catheter is moved forward in the direction of arrow35 and rotated in the direction of arrow 36.

Referring to FIG. 8C, which shows the details somewhat enlarged, force37 is applied to stylet 9A after screw tip 33 has securely engaged thefree end of lead 11 to draw it into the chamber 14 (FIG. 3) of graspingcatheter 1.

Usually, the claws 9 and stylets 9A or the loop 22 or the screw tip 33would be made of flexible stainless steel. It is anticipated that otherforms of grasping elements or control elements therefor will be designedas the technology develops.

The lead grasping catheter tube 1A is of slightly larger outsidediameter than the insulating sheath of the lead 11. As will becomeapparent, the length of the grasping stylets 9A and the catheter tube 1Amust be longer than the subsequently described dilating catheter 3,which has a still shorter ensheathing catheter 5 thereon.

FIGS. 15A-15C illustrate the use of another lead grasping device whichis referred to by reference numeral 87, and is referred to as a"basket". Devices of this general type are commercially available andare used for capturing gall stones. Basket 87 includes a plurality ofstainless steel, flat spring elements 89 which at their proximal end areconnected together to a stylet 91. Arc-shaped spring members 89 are alsoconnected together at their rear end by means of a collar, to which isattached the proximal end of a semi-rigid catheter 93. Control stylet 91extends through the center of catheter 93. Basket 87, as shown in FIG.18A is shown in its normal position (with no tension being applied tocontrol stylet 81) adjacent to a free end of endocardial lead 11 whichis to be extracted. In use, the stylet 91 and catheter 93 extend throughthe center of lead grasping catheter tube 1A, as indicated in dottedlines in FIG. 15C. Basket 87 extends beyond the enlarged chamber 14 atthe reinforced end 7 of grasping catheter 1. To actuate basket 87 as agrasping mechanism, the user applies a tensile force 94 to the distalend of control stylet 91, while maintaining an opposing force 95 on thedistal end of semi-rigid catheter 93, thereby causing the arc-shapedspring elements 89 to bow outward in the directions of arrows 96, asshown in FIG. 15B. This allows the free end (or some other portion) oflead 11 to fit between any of the gaps between adjacent arc-shapedsprings 89, as shown in FIG. 15B. Once this configuration has beenachieved, the next step in the method of use of basket 89 is to releasethe tension on control stylet 91, causing the arc-shaped spring elements89 to collapse in the direction of arrows 97, as shown in FIG. 15C,whereby the two arc-shaped springs 89 tightly close upon and tightlygrasp a portion of endocardial lead 11. Finally, by applying a force inthe direction of arrow 99 to both the semirigid catheter 93 and controlstylet 91, the entire basket 87 with lead 11 grasped thereby can bepulled into the reinforced enlarged chamber 14 at the proximal end ofgrasping catheter 1. This causes the arc-shaped springs 89 to close evenmore tightly on lead 11. If by chance the free end of lead 11 extendsout of the gap between two adjacent arc-shaped springs 89 the leadingedge of reinforced tip 7 of grasping catheter 1 will engage that portionof the lead 11, forcing it to the forward-most portion of the gapbetween the two arc-shaped leads 89 between which lead 11 is lodged, asbasket 87 is drawn into enlarged chamber 14, even further improving thesecureness with which basket 87 grasps lead 11.

Next, the dilating catheter 3 and its ensheathing catheter 5 will bedescribed with reference to FIGS. 9-13A.

The leading or proximal end of dilating catheter 3 includes a radiopaquetip portion 39 by means of which the position of dilating cather 3 canbe fluoroscopically visualized as the lead extracting assembly 2 (FIG.14A) is advanced through the venous pathway. The extreme leading end ofdilating catheter 3 has a smooth edge designated by reference numeral40. As seen best in FIG. 10, sharp outward serrations or ridges 40A forseparating venous scar tissue from lead 11 are disposed over the tip ofdilating catheter 3 behind smooth leading tip 40. This tip can becomposed of plastic, or metal, such as stainless steel in the form of aninsert which slides into the end portion of dilating cather 3. It isessential that the leading edge 40 of dilating catheter 3 be very smoothin order to avoid cutting into the relatively soft outer sheath of leadgrasping catheter 1, especially when catheter 1 is bent, as dilatingcatheter 3 slides forward over lead grasping catheter 1. It is alsonecessary that the sharp serrations or ridges or teeth 40A be providedbehind the smooth leading edge 40 so that as dilating catheter isrotated in opposite directions indicated by arrows 47 as it is advanced,the serrations or ridges 40A will separate scar tissue in the venouspathway from the surface of lead 11.

The leading tip of outer ensheathing catheter 5 also has a smoothleading edge with sharp outward serrations designed by reference numeral43. Immediately following smooth leading edge 43 are a plurality ofspaced sharp serrations or ridges 43A similar to serrations 40A. Thesharp outward oriented serrations 40A and 43A extend from just behindthe smooth leading edges of the respective catheters to a distancebehind the leading edges in order to ensure effective separation of themost dense and/or adherent channel scar tissue likely to be encountered.Ensheathing catheter 5 has an inside diameter that closely matches theoutside diameter of dilating catheter 3A up to the beginning of atapered end portion 3A. FIG. 9 shows an enlarged view of the leading endof dilating catheter 3 and ensheathing catheter 5. In FIG. 9,endocardial lead 11 is assumed to be attached in the manner previouslydescribed to the leading end of lead grasping catheter 1. It is assumedthat dilating catheter has been slid over the grasped end of lead 11 andhas further been slid a distance along its surface.

The inner channel surfaces of catheters 3 and 5 are very smooth to allowsmooth sliding thereof. If needed, suitable lubricants, such ashydrophillic compounds, are used to coat the surfaces.

The configuration of the trailing end of the lead extracting assembly 2is shown in FIG. 13 after lead 11 has been drawn entirely through thechannel of dilating catheter 3.

The distal end of dilating catheter 3 is attached to a first torquingknob or handle 45, the outer edge of which is roughened to enable theuser to easily grasp it between his thumb and forefinger. A measurementscale 46 is printed on the surface of inner knob 45.

The user can, by grasping inner knob 45 between his thumb and fingers,rotate inner knob 45 and thereby also rotate dilating catheter 3 in thedirections indicated by arrows 47 in FIGS. 9 and 10. As subsequentlyexplained, the sharp, outward serrations 40A thereby separate scartissue that is adherent to lead 11. The tapered end portion 3A ofdilating catheter 3 then effectively dilates a venous pathway throughthe scar tissue therein. This allows free passage of the lead extractingassembly 2 into and out of the heart.

Referring again to FIG. 13, an outer knob or handle 49 is attached toensheathing catheter 5, so that when outer knob 49 rotates in thedirection of arrows 50 (FIG. 13), ensheathing catheter 5 correspondinglyrotates in the directions indicated by arrow 51 in FIG. 9.

A removable locking pin 53 extends through a hole in outer knob 49 intoa corresponding hole in inner knob 45 to thereby lock inner knob 45 andouter knob 49 during the initial part of the lead removal process.Later, pin 53 is removed in the direction indicated by arrow 54 (FIG.13) to allow outer knob, 49 and ensheathing catheter 5 to be rotatedindependently of inner knob 45 and dilating catheter 3.

To better understand the environment in which endocardial lead 11 existsand from which it must be removed, FIG. 11 shows a diagrammatic view ofa heart in dotted lines. Reference numeral 56 generally designates theright ventrical. Reference numeral 51 designates a lead tip that isembedded by scar tissue to the myocardial trabeculations. Referencenumeral 59 designates the vein through which the lead 11 is to beremoved. In FIG. 11, the lead extracting assembly 2 is already partiallyinserted into the right ventrical. Detail 12 is shown in enlarged formin FIG. 12, giving a good view of the leading tapered end 3A of dilatingcatheter 3 and the leading portion of the ensheathing catheter 5 priorto removal of locking pin 54 (FIG. 13) to allow lateral and rotarymovement of outer 49 relative to inner knob 45 in the directionsindicated by arrows 60 and 50, respectively.

In FIG. 11, reference numeral 51A designates flexible tines of the typepreviously described, which are molded from the flexible material ofwhich the outer sheath of endocardial lead 11 is made in order tofacilitate formation of scar tissue embedding the tip 51 of lead 11 intothe trabeculations of the myocardial tissue.

FIG, 13A is a partial sectional view of the lead extracting assembly 2with the grasping claws 9 positioned about the free end of lead 11, butbefore they have been drawn into enlarged chamber 14 of lead graspingcatheter 1.

It should be noted that the inner channel of dilating catheter has verylow friction, which can be created by providing very smooth matingsurfaces on the semi-rigid but flexible material from which the dilatingcatheter is formed or, as previously mentioned, by a special innercoating of hydrophyllic material. The friction needs to be low enoughthat it allows the channel dilator 3 to pass over the surface ofgrasping catheter 1 and also the outer surface of the endocardial lead11 which is to be removed from the patient's heart. The same is true ofthe inner surface of ensheathing cather 5. The dilating catheter 3 andensheathing catheter 5 can, for example, be composed of the same generaltype of low friction coefficient material of which the well knownsubsequently described COOK introducers are commonly made. The outwardserrations can be molded from the same material, if desired, instead ofusing stainless steel inserts. In the configuration of the leadextracting assembly 2 at the beginning of the lead extraction procedure,the outwardly serrated end of the ensheathing catheter is positioned atthe point where the tapered portion 3A of the dilating cather 3 begins,as shown in FIG. 14B.

To explain one example of the method of the present invention, the leadextraction assembly 2 is used in a typical situation in which the upperor distal end of the lead 11 to be removed is disconnected from thepulse generator or pacemaker device. The free end of that lead is freedof tissue down to the venous access port (unless the lead has beenbroken inside the venous pathway or in a chamber of the heart; theprocedure for removal in this case is described subsequently). All ofthe usual ties around the lead sheath are removed.

The patient has been placed on a fluoroscopy table for visualization (bymeans of X-rays) of the position of the faulty lead in the venouschannel on the heart. The helical coil through the center of the lead tobe removed makes X-ray visualization of its position possible. Usually,the skin in the pectoral area where the pulse generator is implanted isopened. The pulse generator is removed. The connector assembly thatconnects the lead to the pulse generator is cut off. The cut free end ofthe lead can be grasped by any of the above-mentioned embodiments of thelead grasping mechanism. If the grasping claws 9, shown in FIGS. 1-3,are utilized, the lead end protruding from the access hole in the veinis grasped as shown in FIG. 3 and pulled into the enlarged chamber 14 ofthe lead grasping catheter 1. The stylets 9A then all are bent aroundand into the respective grooves 19 of the stylet locking head 18 (in themanner previously explained) to retain the grasping claws 9 and free endof lead 11 securely in enlarged chamber 14 (FIG. 3).

At this point, it will be helpful to refer to FIGS. 14A-14F, whichdiagrammatically illustrate in simplied form the heart and veinstructure shown in FIG. 11. At this point in the method of theinvention, the lead extracting assembly 2 is positioned generally asindicated in FIG. 14A. Reference numeral 65 designates channel scartissue in vein 59.

Referring next to FIG. 14B, the physician applies traction or tension tolocking head 18 in the direction of arrow 66 to hold it, lead graspingcatheter 1, and lead 11 stationary. The outer ensheathing catheter 5 andthe dilating catheter 3 within it are moved together into vein 59 in thedirection indicated by arrows 67. The leading or proximal end dilatingcatheter 3 then are slid over the grasped end 11A of lead 11. Rotationaltorque in the direction of arrows 68 is applied back and forth to knobs45 and 49, which at this point in the procedure are locked together bypin 53 of FIG. 13. This causes the outward serrations 40A and 43A ofdilating catheter 3 and ensheathing catheter 5, respectively, to rotateas indicated by arrows 69. The rotation of the serrations 40A ofdilating catheter 3 separate the scar tissue 65 that is adherent to theouter surface of endocardial lead 11. As the rotating dilating catheter3 is forced further into vein 59 and scar tissue 65, the tapered portion3A dilates the scar tissue, forming a channel therethrough. Eventually,the outward serrations 43A of ensheathing catheter 5 further dilate thechannel through the scar tissue 65. Note that up to this point, theposition of endocardial lead 11 in the right ventrical 56 of thepatient's heart has been unchanged, and tip 51 remains embedded in scartissue in the myocardial wall.

Referring to FIG. 14C, the previously described advancing of dilatingcatheter 3 and ensheathing catheter 5 continues under fluoroscopecontrol until the radiopaque tip 39 is determined to be positionedimmediately adjacent to embedded tip 51. At this point, it can be seenthat the handles 45 and 49 and the respective catheters attached theretohave been advanced together over the entire length of the lead graspingcatheter, so that the free end of endocardial lead 11 extends out of thehole at the upper end of inner knob 45. All of the scar tissue along thevenous path 59 has been separated from the lead and dilated, and theentire endocardial lead 11 except tip 51 now is located inside dilatingcatheter 3. Tip 51 remains embedded by scar tissue in the trabeculationsof the myocardial wall.

Referring now to FIG. 14D, the next step is to remove pin 53 (see FIG.13). Then, outer knob 49 is slid forward relative to inner knob 45 inthe direction indicated by arrow 79 from the position indicated bydotted line 77 to the position indicated by reference numeral 49. Asthis is done, outer knob 49 is rotated in the direction of arrows 75.The scale 46 (see FIG. 13) printed along inner handle 45 is carefullyobserved. Also, the radiopaque portion 42 of the tip 42 of ensheathingcatheter 5 can be carefully visualized under fluoroscopic control. Therotation of knob 49 with inner handle 45 being held stationary resultsin rotation of the sharp outward serrations 43A, causing them to helprotate and thereby separate a cylindrical region in the scar tissue fromembedded tip 51 if this scar tissue is not simply torn loose and pushedaway from tip 51 in response to the downward force applied to that scartissue by the smooth, blunt leading edge 43 of catheter 5, (which alsoguards against accidental cutting of a hole in the myocardial wall).Observation of the scale 46 and utilization of a stop 81 which is on thelower end of inner knob 45 limits the downward movement of outer knob 49and prevents outward serrations 43A and smooth edge 43 of ensheathingcatheter 5 from damaging the wall of the heart.

FIG. 14E shows a cutaway enlarged view of the outward serrations 43Aseparating the scar tissue that lodges tip 51 in the myocardial wall. InFIG. 14E it can be seen that the leading edge 43 of ensheating catheter5 forces tines 51A forward. In some instances, this forward flexing oftines 51A contributes greatly to dislodging the tip and electrodethereof from the scar tissue.

Ordinarily, even for porous lead tips which are sometimes used, the scartissue connecting the extreme end of the tip 51 to the myocardial wallis weak enough that the entire lead extraction assembly 2, with theendocardial lead 11 and tip 51 therein can be simply withdrawn out ofright ventrical 56 and through the venous pathway 59 in the direction ofarrows 70, as shown in FIG. 14F. After the entire assembly and lead havebeen withdrawn from vein 59, the lead removal process has beencompleted--without opening the chest of the patient and incurring therisks attendant such operative procedures.

If the lead 11 is broken either in the venous pathway 59 or in a chambersuch as 56 of the patient's heart, the above-described procedure ismodified by introducing the lead extraction assembly 2 into the vein ina manner which is somewhat conventional in that leads are sometimesintroduced in this manner. The first step is to stick an 18 gauge (forexample) hollow needle through an appropriate point of vein 59. Next, aflexible guide wire of the type supplied with an introducer known as a"COOK introducer" is inserted through the hollow 18 gauge needle intothe venous pathway and is guided, with the aid of X-ray visualization,to the free end of the broken lead 11 to be extracted. The 18 gauageneedle then is removed by pulling it outward from the vein and slidingit over the guide wire of the COOK introducer, which is held in itsplace so that its proximal tip remains adjacent to the free end of thebroken lead 11 in the patient's vein or heart cavity. Next, the dilatingcatheter is slipped over the guide wire, along with an ensheathingcatheter of the COOK introducer disposed over the dilating catheterthereof. The COOK introducer then is slid over the guide wire into thevein, so that the leading portion of the COOK introducer follows theguide wire to a location adjacent to the free end of broken lead 11. Theguide wire and the dilating catheter are slid out of the ensheathingcatheter of the Cook introducer, thereby leaving an open channel throughthe venous pathway to the free end of the broken lead.

The lead extracting assembly 2 of the present invention then is insertedthrough the open pathway of the ensheathing catheter until the leadingend 7, which is radiopaque in this embodiment of the invention, ispositioned adjacent to the free end of the broken lead 11. The graspingmechanism (e.g., the claw arrangement of FIG. 1 or the loop arrangementof FIGS. 6A, B or the basket arrangement of FIGS. 15A, B, C) is extendedby means of the distal end of the stylet wires 9A around the free end ofthe broken lead and manipulated to engage the free end, draw it into thechamber 14 of the dilating catheter 1, and bend the stylet wires 9Aaround the stylet locking head 18 into the grooves 19 thereof, aspreviously explained.

Once the free end of the broken lead 11 has been thus grasped, drawninto chamber 14, and made essentially integral with the lead graspingcatheter 1, the remaining steps in the process of extracting that leadare the same as previously described for advancing the dilating catheter3 and the ensheathing catheter 5 to further dilate the venous pathway,if necessary, and cut through scar tissue surrounding the embedded tip59 and then remove the lead extracting assembly 2 and lead 11 therein asa unit through the ensheathing catheter of the COOK introducer.

It should be noted that in some cases, outward serrations on the lips ofthe dilating and/or ensheathing catheters might not be needed at all, oneither the dilating catheter 3 or the ensheathing catheter 5.Furthermore, in some instances, the dilating catheter might be omitted,and the ensheathing and the lead grasping catheter might be the onlyones required. This could be the situation if it is known that there isnot a significant amount of scar tissue in the venous pathway. In thisevent, only the outer ensheathing catheter with its serrated leadingedge 43 need be disposed about the lead grasping catheter 1 in order tocut the scar tissue embedding the tip 51 in the myocardial wall tissue.Alternatively, if it is known that the tip 51 is not tightly lodged byscar tissue to the myocardial wall, or if one of the above-mentionedMedtronic screw-in/screw-out tips is utilized, the outer ensheatingcatheter can be omitted, but the dilating catheter might be needed toseparate channel scar tissue in the venous pathway from the outersurface of the lead before it can be rotated tounscrew in electrodes.

It is plausible that a lead grasping apparatus which is not a catheterat all can be used if the free end of the endocardial lead to be removedis available at the connection point to the pulse generator. Thegrasping tip could be manually clamped to the available free end of theendocardial lead at the proximal end of the lead grasping apparatus,rather than by means of control stylets passing through the center of alead grasping catheter. In this case, the catheter sheath portion of thelead grasping apparatus is not needed. However, it must be long enoughto extend entirely through the distal end of the dilating catheter sothat the distal end of the lead grasping apparatus can be heldstationary to maintain both the lead grasping mechanism and theendocardial lead grasped thereby substantially stationary as thedilating catheter and the ensheathing catheter are advanced through thevenous path into the heart.

In the event that a composite dual lead assembly of the type describedin my U.S. Pat. No. 4,332,259 is in place in the patient and needs to beremoved, the above-described lead extracting assembly 2 can be utilized,but first it is necessary to sever one of the leads of the compositeassembly from the other. In order to understand how this is done, abrief description of the composite lead assembly is necessary. Referringnow to FIG. 16A, dual composite lead assembly 100 includes a channellead 101 and a core lead 102. Typically, the lower portion of thechannel lead 101 extends into the coronary sinus or the atrial appendageof the patient's heart, an the core lead 102 extends to a tip that isembedded in the trabeculations of the myocardial wall in the rightventricle. The core lead exits through a side port 103 in the channellead, as described in more detail in U.S. Pat. No. 4,332,259 issued June1, 1982 to the present inventor, and incorporated herein by reference.

In accordance with the present invention, since the dilating catheter 3cannot slide beyond the junction at which the core lead 102 departs fromthe channel lead 101, it is necessary prior to the utilization of thelead extracting assembly 2, to introduce a COOK introducer (not shown)into the vein (in the manner previously explained) to provide anopen-channel sheath or shaft from the venous access point to a point atwhich it is desired to sever the core lead 102. Once the open channelsheath of the COOK introducer is in place, another catheter 105 isinserted through the open sheath so that its lower end 105A is adjacentto the portion of core lead 102 to be severed, as illustrated in FIG.16A. At this point, it will be helpful to refer to FIG. 16B, which is asectional view of the lower portion 105A of catheter 105. Lower cathetersection 105A has a sickel-shaped retractable knife 106 therein with avery sharp inner knife edge 106A. The upper portion of sickel-shapedknife 106 is attached to a stylet 108 that extends through the center ofcatheter 105 and can be manipulated from the distal end of catheter 105to extend or retract knife 106.

A pair of spaced bars 109 are rigidly disposed inside the lower openingof catheter 105A and act as a pair of stops between which knife 106extends.

In use, the metal knife 106, which can be visualized by fluoroscopy, ispositioned so that its knife edge 106A loops around a portion of corelead 102, as shown in FIG. 16A. The surgeon then applies tension onstylet 108 at the distal end of catheter 105 to produce a force 110thereon. The force 110 is counterbalanced by an opposite force 111applied to the catheter 105. This causes core lead 102 to be drawn upagainst stops 109. As the surgeon increases the tension on stylet 108,the razor-sharp knife edge cuts through core lead 102 as knife edge 106moves upward in the direction indicated by arrow 112. At this point,catheter 105 and knife 106 therein can be withdrawn. The lower portionof lead 102 is thus free, and can be subsequently grasped by means of alead grasping mechanism of lead grasping catheter 102 in the mannerpreviously described. If desired, core lead 102 can be withdrawn intothe channel of channel lead 101 in the direction indicated by arrow 113.Then the techniques previously described can be utilized to extract bothchannel lead 100 and the lower portion of core lead 102 from thepatient.

Although the above-described lead extracting assembly and techniques forits use do not eliminate all of the risks previously attendant to leadextraction, the procedures and apparatus described herein are believedto substantial reduce the risks which are attendant to previous methodsof lead extractions, especially open chest surgery.

While the invention has been described with reference to severalparticular embodiments thereof, those skilled in the art will be able tomake various modifications to the described apparatus and methodswithout departing from the true spirit and scope of the invention.

I claim:
 1. An apparatus for removing an endocardial lead from the heartof a patient via a venous path, said endocardial lead having a free endand a distal end with a tip that is lodged in tissue in said heart, saidapparatus comprising in combination:(a) first catheter means, having adistal end and a proximal end, for insertion into a venous path to saidheart; (b) lead grasping means for grasping a portion of saidendocardial lead distant from said tip; (c) stylet means extendingentirely through the length of said first catheter means and connectedto said lead grasping means for manipulating of said lead grasping meansfrom said proximal end of said first catheter means and drawing of saidlead grasping means and a grasped portion of said endocardial lead intosaid distal end of said first catheter means and lodging said graspedportion of said endocardial lead in said distal end of said firstcatheter means; (d) stylet tension maintaining means disposed at theproximal end portion of said first catheter means for maintainingsufficient tension on said stylet means to cause said lead graspingmeans and said grasped portion of said endocardial lead to remain lodgedinside of said distal end of said first catheter means and insecurelyattached relationship to said distal end of said first catheter means;(e) second catheter means disposed concentrically about said firstcatheter means for controlled advancement over said first catheter meansand said endocardial lead toward said tip and for engaging the tissuesurrounding said tip and pushing said tissue surrounding said tip awayfrom said tip to separate that tissue from said tip, said secondcatheter means having a distal end and a proximal end; (f) first meansfor effecting controlled advancing of said second catheter means oversaid first catheter means and said endocardial lead toward said tip; and(g) second means for effecting controlled advancing of said distal endof said second catheter means over said distal end of said firstcatheter means into sid tissue surrounding said tip and for effectingcontrolled rotation of said second catheter means relative to said firstcatheter means, to further effectuate said separating of said tissuefrom said tip.
 2. A method of removing an endocardial lead from theheart of a patient via a venous path, said endocardial lead having afree end and a distal end with a tip that is lodged in tissue in saidheart, said method comprising the steps of:(a) providing a lead graspingassembly including a first catheter having a proximal end and a distalend, lead grasping means for grasping a portion of said endocardiallead, and stylet means extending entirely through the length of saidfirst catheter for controlling said lead grasping means, the portion ofsaid stylet means extending from said distal end of said first catheterbeing connected to said lead grasping means; (b) providing a secondcatheter concentrically about said first catheter, said second catheterhaving a proximal end and a distal end; (c) passing said lead graspingassembly through a venous path to advance said lead grasping means tosaid free end of said endocardial lead; (d) manipulating said styletmeans at said proximal end of said first catheter to cause said leadgrasping means to grasp said free end of said endocardial lead; (e)manipulating said proximal end of said second catheter to advance saiddistal end of said second catheter over said distal end of said firstcatheter, said lead grasping means, and said free end of saidendocardial lead and toward said tip to cause said distal end of saidsecond catheter to engage tissue surrounding said lodged tip and pushsaid tissue away from said tip to separate said tissue from said tip;and (f) withdrawing said lead grasping assembly to remove saidendocardial lead from said heart.
 3. An apparatus for removing anelongated foreign article from a patient's body via a venous path, saidapparatus comprising in combination:(a) a first catheter, having adistal end and a proximal end, for insertion into a venous path in thepatient's body; (b) grasping means for grasping a portion of saidelongated foreign article; (c) stylet means having a proximal end and adistal end and extending entirely through the length of said firstcatheter and connected to said grasping means for manipulating of saidgrasping means from said proximal end of said first catheter and drawingof said grasping means and a grasped portion of said elongated foreignarticle into an enlarged opening in said distal end of said firstcatheter means, said grasped portion of said elongated foreign articlebeing small enough and/or flexible enough to allow said grasped portionto be drawn into said enlarged opening in said distal end of said firstcatheter means; and (d) stylet tension maintaining means disposed at theproximal end portion of said first catheter for maintain sufficienttension on said stylet means to retain said grasping means and saidgrasped portion of said elongated foreign article in said enlargedopening in said distal end of said first catheter and in securelyattached relationship to said distal end of said first catheter, suchthat said first catheter effectively becomes an extension of saidelongated foreign article.
 4. The apparatus of claim 3 wherein saidstylet means includes a semi-rigid second catheter extending throughsaid first catheter, and said stylet means also includes a flexiblestylet wire extending through said second catheter, and said graspingmeans includes a plurality of flexible, elongated spring membersdistinct from said stylet means and each having a first end and a secondend, the first end of each of said spring members being attached to saiddistal end of said second catheter, the second end of each of saidspring members being connected to said distal end of said stylet wire,said manipulation of said stylet means from said proximal end of saidfirst catheter means causing flexing of said spring members to cause themidportions of said spring members to bow outwardly to form a basket andthen return to a collapsed configuration wherein a portion of saidelongated foreign article is ensnared between two adjacent ones of saidspring members.
 5. The apparatus of claim 4 wherein said spring membersare initially substantially straight, and are bowed outwardly by pullingon said proximal end of said stylet means, and are collapsed to ensnaresaid elongated foreign article by releasing or pushing said proximal endof said stylet means.
 6. A method for removing an elongated foreignarticle from a patient's body via a venous path, said method comprisingthe step of:(a) providing a first catheter for insertion into a venouspath in the patient's body, said first catheter having a proximal endand a distal end; (b) providing a grasping means for grasping a portionof said elongated foreign body; (c) providing a stylet means extendingentirely through the length of said first catheter, a distal end of saidstylet being connected to said grasping means to effectuate manipulatingof said grasping means from said proximal end of said first catheter anddrawing of said grasping means and a grasped portion of said elongatedforeign article into an enlarged opening in said distal end of saidfirst catheter, said grasped portion of elongated foreign article beingsmall enough and/or flexible enough to allow said grasped portion to bedrawn into said enlarged opening in said distal end of said firstcather; (e) passing said first catheter, said grasping means and saidstylet means into the venous path to advance a portion of said graspingmeans to a portion of said elongated foreign article; (f) manipulating aproximal end of said stylet to open a grasping portion of said graspingmeans and close it upon a portion of said elongated foreign article; (g)pulling said grasping means and the grasped portion of the elongatedforeign article into said enlarged opening and maintaining tension onsaid stylet means to draw said lead grasping means and said graspedportion of said elongated foreign object into said enlarged opening andmaintain said elongated foreign object in securely attached relationshipwith the distal end of said first catheter so that first cathetereffectively becomes an extension of said elongated foreign object; and(h) withdrawing said first catheter, said grasping means said stylet,and said elongated foreign object as a unit out of said venous path. 7.The method of claim 6 including providing a semi-rigid second catheterextending through said first catheter and a flexible stylet wireextending through said second catheter, and providing on said graspingmeans a plurality of flexible, elongated spring members distinct fromsaid stylet means and each having a first end attached to a peripheralend portion of said second catheter and a second end attached to adistal end of said stylet wire, said method including pulling on saidstylet means from said proximal end of said first catheter to causeflexing of said spring members to cause their midportions to bowoutwardly to form a basket, and causing said means to move said distalend of the stylet wire outward to cause said spring members to return toa collapsed configuration wherein the grasped portion of the elongatedforeign article is ensnared between two adjacent spring members.